php return image from url

I want to return an image over an URL like http://ift.tt/1nSnYrV. I have my URL http://ift.tt/1EovAhh, which calls an action on controller. The controller get some data (name, id, etc.) from database and also a binary string of the image content.

On the frontend site, i have my img tag, where i want to call the url in my src attribute.

<img src="http://ift.tt/1EovAhh">

Some more information, i use slim PHP Framework and my server is an ubuntu 13.x system (vagrant etc.). I am an typically frontend developer and dont have good skills @ PHP.

Following snippets works:

$file = fopen($name, 'wb');
fwrite($file, $binaryData);
fclose($file);

but I dont want to generate files in a directory. Is this possible?

EDIT: Content-Type and Content-Length Headers are set, that is not the problem.